First go into the event layer and make a new event then you choose the evan graphic, (and if you look for it there is already an sprite of a closed, open and opening chest, its at the bottom in a file called "Chest01" or 02,03)
Once you have chosen the closed chest graphic make a command called "Move event" makes sure you look in the top corner of the box that pops up, and change it to "This event" then click "Change graphic" change it to the icon of it opening, then click wait, make it wait 2 frames and this will stop it from moving to fast. And keep repeating this proces untill the chest is open
Now when you walk up to the chest and click the action button the chest will open! And this is basicly all i know so far im not sure how to make it so you can search it yet but i've messed around with it abit and i think if you make the first command "Show choices" and name choice 1 "Open" and the other "Close" then you put the command of it opening into the "open" section and do it with the close one, and hopefully you can now close it aswell, not 100% sure on that one